1. Field of the Invention
The present invention relates to a car battery array carried on-board an automobile to supply power to the car driving motor.
2. Description of the Related Art
A car battery array has many individual battery cells connected in series to raise the output voltage. The purpose is to supply a large amount of power to the driving motor. This type of battery array is provided with many high capacity battery cells resulting in a large overall weight. Individual battery cells are housed in an external case and carried on-board the automobile. A battery array with this type of structure is described, for example, in Japanese Laid-Open Patent Publication No. JP 2008-53149 A.
FIG. 1 shows the battery array of JP 2008-53149 A. This battery array has many battery cells 91 stacked together and housed in an external case 99. The external case 99 has a lower frame plate 93 and an upper cover plate 94. The cover plate 94 is attached to the frame plate 93 to form the external case 99 having a battery compartment 96. Battery cells 91 housed in this external case 99 are mounted on top of the frame plate 93. In this type of battery array configuration, the entire weight of the heavy battery cells is placed on the frame plate. Consequently, the frame plate must have an extremely strong composition, and more specifically, it must be made of thick metal plate. This has the drawback that the external case becomes extremely heavy.
The present invention was developed with the object of correcting this drawback. Thus, it is a primary object of the present invention to provide a car battery array that has an overall light weight and strong construction while housing many heavy batteries.